Most motor vehicles include air vents which include a mechanism for directing air flow from the vent. One such design comprises an "eyeball-type" vent comprising a part spherical nozzle capable of swivelling within a part spherical housing. Various mechanisms have been proposed for providing universal rotation of the nozzle with respect to the housing. One example of such a mechanism is a gimbal which is pivotally mounted to the housing about a first axis and the nozzle is pivotally mounted to the gimbal about a second axis orthogonal to the first axis.
One example of such an air vent is described in UK Patent 1 478 226 in which an annular gimbal ring surrounds the spherical surface of the nozzle shell and lies within the housing and is pivotally connected at diametrically opposite regions to the nozzle shell and pivotally connected at diametrically opposite regions to the housing with the respective pivot connections pivoting on axes in the same plane but at right angles to each other. The gimbal ring must be carefully fitted between the housing and the nozzle and the alignment of the four pivot connections must be accurate for proper operation.